Any theatregoer who's seen enough solo shows knows that all extemporaneously performed one-man plays are not created equal. But rarely is that lesson hammered in as dramatically - so to speak - than right now at The Public Theater. Mike Daisey's meditation on the necessary evils of capitalism, The Last Cargo Cult, which opened at The Public Theater's Newman Theater last week, is a masterfully crisp rendition of a dodgily conceived subject. Roger Guenveur Smith's Juan and John, which just opened literally across the lobby at the Shiva Theater, is built on an ingenious theme that's sabotaged by inchoate writing and unmoored acting.

That idea, not to put too fine a point on it, is racism. Not unusual for a play in New York, you say? At The Public, no less? No, probably not. But Smith peers at the racial divide that exists between the two most politically prominent non-white ethnic groups of the last half-century: African- and Latino-Americans. And he does it through the appropriate lens of the American Pastime, specifically regarding a game on August 22, 1965, when "Dominican Dandy" Juan Marichal of the San Francisco Giants introduced Los Angeles Dodgers catcher Johnny Roseboro's forehead to the business end of a baseball bat.

The ensuing enmity, which would span decades, is a crystalline statement about the rocky nature of United States race relations, and one that's neither condescending nor overrepresented. Smith's notions of using this encounter to examine the evolution of tolerance and threading his then-perspective of the incident as a young, light-skinned black boy - and intense Johnny Roseboro fan - into a broader cultural critique are incredibly smart. It's the kind of satisfying theatrical Connect-the-Dots that the better solo artists, including Daisey at his most astute, play with a well-deserved relish.

Smith, alas, never gets that far. Unlike Daisey, who always works from notes but never seems to need them, Smith has chosen to work without a safety net and behaves like his trapeze just snapped in mid-arc. His audience-interaction segments, many inquiring if onlookers know certain locations in his native Los Angeles, are bafflingly disconnected affairs. His speech is constantly halting, as though he's always searching for the best word to use and failing to find it, and delivered toward random corners of the theater rather to the audience. And, at least at the performance I attended, Smith both visibly lost his place more than once, and was almost always on the verge of running out of breath entirely.

Because Smith evinces no confidence about his own presence, he does little to instill in you any particular faith or involvement in the events he relates. More serious still is that he's organized the play in so scattered and overwritten a way that that potentially dynamite premise can barely be located in the first place.

A 10-minute montage in which Smith recounts Marichal's and Roseboro's lives in their own (unimaginatively recreated) voices could probably be accomplished in a handful of third-person sentences. Yet another outing, when Smith plays Roseboro (metaphorically) recanting on his (literal) deathbed, drags almost as much in making a point that's restated much more effectively a scene later anyway. Smith's attempts to inject to draw generations-spanning parallels by describing his troubled dealings with his daughter fall flat because they have no direct connection to his central thesis. And are the interpretive dance interludes between scenes absolutely necessary?

Marc Anthony Thompson's video projections support Smith's underlying narrative about the play's title characters' roles in the dialogue about national discrimination, as well as his own (distant) part of that conversation. But almost all the writing and production's other trappings feel like traps, restricting rather than setting free a resolutely American tale that's worth telling but has rarely (if ever) been dramatized. If Smith can refashion what's here into a single, clear, and personal narrative, without all the decorative fat, this attractive mess could be a stunning solo tour de force.

That goal is not necessarily out of Smith's grasp. As part of the Public LAB developmental series, the show is likely still in flux. (This may also explain Smith's difficulty wrangling it, even if it's not an excuse; other Public LAB shows, such as this past Spring's Bloody Bloody Andrew Jackson, have looked transfer-ready from the get-go.) It's unlikely that Smith will ever be Daisey - but that's a good thing: Smith's outlook and point of view are distinctive and original, and deserve to be heard. Right now, however, Juan and John's excess is making them far too hard to hear.

Juan and JohnThrough December 20
Public Theater, 425 Lafayette Street
Tickets online and current Performance Schedule: Public Theater